She can believe that cutting her hair is wrong, but she doesn't get to tell you that you shouldn't cut your hair. Same with the other things, although they are bad habits they are not "wrong" for you to do because her religion says so. Her religious beliefs are hers, and unless you share them you are under no obligation to live by them. She will hopefully figure that out at some point. I'm an atheist, but i do have an example of something that while not a religion gave me a similar mindset to your friend. When I was in high school, I stopped eating meat. For a number of reasons, including being bullied for a love for animals. The next year or so, I drove my meat eating family and friends nuts by becoming "preachy" about vegetarianism. Telling them what they were eating was wrong and so on. Eventually, I learned that I had to respect their choices and not try to change them to my point of view if I wanted to keep my relationships. I haven't eaten meat since, they all still eat meat, and that's okay. Hopefully you and your friend can reach a compromise in which you stay friends and respect each other's religion/lack of religion.